Harvest 

As a bonus action after dropping a creature to 0 hit points, the harvester can harvest something useful from their corpse. Gaining one potion of common rarity, or a flask of acid.If the creature was a slaad, they can harvest their control gem instead.

Bodily knowledge 

The harvester scores a critical hit on 18-20, and a creature that gets critically hit by it is paralyzed until the start of the harvester's next turn.

Doctor's Expertise

The harvester can cast spare the dying at will, as a bonus action instead of an action.In addition, the harvester can use their intelligence modifier when making medicine checks, instead of wisdom.

Multiattack. The harvester makes Three dagger attacks or one shortsword attack at advantage.

Dagger. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 3 (1d4 + 1) piercing damage.